Pressure gauge

ABSTRACT

A pressure gauge in the form of two pressuretight compartments separated by a flexible diaphragm in which the gauge housing serves as the low-pressure chamber and a cover member secured to the housing over the diaphragm defines the high-pressure chamber. The gauge range spring is a leaf spring anchored to the housing at one of its ends with the other end of the spring carrying a permanent magnet that is disposed adjacent a rotatably mounted helix carrying an indicating arm which cooperates with the gauge scale. The leaf spring is connected to the diaphragm for movement by same, the spring rate of the leaf spring is adjustable externally of the housing by moving a shiftable fulcrum, and zero adjustment is provided including a threaded member actionable from outside the housing. The gauge is designed for low profile by placing both the high- and the low-pressure connections at the low-pressure side of the gauge, and providing for communication through the diaphragm to the high-pressure chamber.

[ 5] Feb. 29, 1972 [54] PRESSURE GAUGE Primary Examiner-Louis R. PrinceAssistant Examiner-Daniel M. Yasich [72] Inventors: James W. Phillips,Michigan City; Richard S. Zoludow, south Bend both of Ind. AttmeyMann,Brown, McWilliams & Bradway [73] Assignee: Dwyer Instruments, Inc. [57]ABSTRACT [22] Filed: June 15, 1970 A pressure gauge in the form of twopressuretight compartrnents separated by a flexible diaphragm in whichthe gauge [2}] Appl' 4614l housing serves as the low-pressure chamberand a cover Related Application Data member secured to the housing overthe diaphragm defines the high-pressure chamber. The gauge range springis a leaf [63] commuatlon'm'pan of 735339 June spring anchored to thehousing at one of its ends with the 1968 other end of the springcarrying a permanent magnet that is disposed adjacent a rotatablymounted helix carrying an inv s v u s v e u s e e e e a u u 1 e 1 s I ee s s spring is connected to the diaphragm for movement by same, [58]Field of Search ..73/407 R, 406, 410, 710 the Spring rate of the leafSpring is adjustable externally of the housing by moving a shiftablefulcrum, and zero adjustment is [56] References cued provided includinga threaded member actionable from out- UNTED STATES PATENTS side thehousing. The gauge is designed for low profile by placmg both thehighand the low-pressure connections at the 3,397,319 8/1968 Locke..73/407 lowPressure side f the gauge, and providing f communica-2,509,644 1950 Kmdefman tion through the diaphragm to the high-pressurechamber. 2,722,837 11/1955 Dwyer ..73/407 16 Claims, 17 Drawing Figures|as\ I 182 i655 40 I 22 i l 34 4a 32 HE 1 e2 \8 |7| A 44 156 I wPATIENTEDFEB 29 I972 SHEET 2 [IF 5- FIGS INVENTORS JAMES W. PHILLIPSRICHARD S ZOLUDOW ATTORNEYS PAIENTEUFEB29 I972 3.645.140

sum 3 OF 5 INVENTORS JAMES W. PHILLIPS RICHARD S. ZOLUDOW AT ORNEYSPATENTEUFEB29 m2 SHEET I [IF 5 FIGIO iNv'EN IORS JAMES W. PHILLIPSRICHARD S. ZOLUDOW BY 77/m 2/Lww71l M ATTO RNEYS PRESSU GAUGE Thisapplication is a continuation-in-part of our pending application Ser.No. 735,339, filed June 7, 1968, now Pat. No. 3,566,060 the filing dateof which is claimed for all subject matter common thereto.

This invention relates to pressure gauges of the type suitable for suchpurposes as, for instance, reading static pressure, total pressure, airvelocity pressure, draft pressure, differential pressure, airresistance, or gas pressure in any equipment involving air movement, andmore particularly relates to a sealed capsule-type gauge of thedifferential pressure type including a flexible diaphragm connected tooperate the sensitive and accurate motion transforming type of indicatormechanism mounted directly in the capsule.

Conventional pressure gauges of the type indicated are ordinarilyarranged so that the highand low-pressure connec tions are on oppositesides of the diaphragm, resulting in a high-profile device. Furthermore,the various parts of same are frequently complex and overly expensive tomake.

A principal object of this invention is to provide a lowprofiledifferential gauge of simplified design.

Another principal object of this invention is to provide a differentialpressure gauge of improved response by minimizing internal gauge volume.7

Still another principal object of the invention is to provide alow-profile differential pressure gauge with improved externallyadjustable range spring and zero adjust arrangements.

Yet other objects of the invention are to provide a pressure gauge ofthe differential pressure type that is economical of manufacture,convenient to apply and use, and long lived in operation.

In accordance with this invention, I have provided a differentialpressure gauge in which the housing has an open end that is closed bythe diaphragm which is in turn covered by a cover member, with thediaphragm thus dividing the instrument into lowand high-pressurechambers, and with the housing diaphragm, and cover being arranged tohave both the highand low-pressure connections at the low-pressure sideof the gauge, and to permit transmission of the high pressure throughthe diaphragm to the high-pressure chamber. The diaphragm is connectedto a leaf spring that forms the range spring of the instrument and isanchored at one end of same to the housing and is provided with asimplified but effective shifting fulcrum for changing the calibrationof the instrument externally of the housing. The leaf spring at its freeend carries a plate magnet that is disposed adjacent a helix formed froma material of high-magnetic permeability that extends substantiallyperpendicular thereto, which plate magnet is adaptedto cooperate withthe helix to rotate same on deflection of the diaphragm. The helix hassecured thereto an indicator which cooperates with the gauge scale forreading the gauge. Associated with he leaf spring is a zero adjustmentarrangement including a threaded element rotatably mounted in the gaugehousing and arranged for external adjustment. All parts of the gauge aredesigned for quick and inexpensive production.

Other objects, uses and advantages will be obvious or become apparentfrom a consideration of the following detailed description and theapplication drawings in which like parts are indicated by like referencenumerals throughout the several views.

' In the drawings:

FIG. 1 is a front view of the front side of a gauge embodying theprinciples of this invention;

FIG. 2 is a rear view of the gauge of FIG. 1, with the diaphragm andhousing back cover removed, showing the general arrangement of thelow-pressure chamber of the gauge in plan (with parts being brokenaway);

FIG. 3 is a diagrammatic cross-sectional view taken substantially alongline 3-3 of FIG. 2, and on an enlarged scale, with the diaphragm, backcover and related parts in place;

FIG. 3A is a diagrammatic sectional view of the body of the connectingdevice shown in FIG. 3 for connecting the diaphragm plate to the gaugerange spring;

FIG. 4 is an enlarged view of the gauge range spring adjustment that isshown in FIG. 3;

FIG. 5 is an enlarged view of the zero adjustment arrangement of FIG. 3;

FIG. 6 is a fragmental cross-sectional view substantially along line 66of FIG. 3 illustrating the magnetic motion translating device of thegauge;

FIG. 7 is a fragmental view taken substantially along line 7-7 of FIG. 2illustrating the manner in which the high-pressure connection of thegauge is connected to the high-pressure chamber of the gauge;

FIG. 8 is a front plan view of the gauge diaphragm, looking at theright-hand side of FIG. 3 and with the diaphragm plate omitted;

FIG. 8A is a fragmental cross-sectional view substantially along line8A8A of FIG. 8, with the diaphragm plate of FIG. 3 shown in place;

FIG. 9 is a rear plan view of a diaphragm for the gauge that is arrangedfor low pressure differential use;

FIG. 10 is a cross-sectional view taken substantially along line 10-10of FIG. 9;

FIG. 11 is a plan view of the housing back cover member showing theinside of same;

FIG. 12 is a plan view of the range spring and magnet assembly, takensubstantially along line 1212 of FIG. 6;

FIGS. 13 and 14 are views similar to those of FIGS. 2 and 3,respectively, illustrating a modified fonn of the invention; and

FIG. 15 is a fragmental view of the helix and associated magnet of theembodiment of FIGS. 13 and 14, taken substantially along line 15-45 ofFIG. 13, and with the helix shown in full elevation.

However, it is to be understood that the specific drawing figuresprovided are supplied primarily to comply with the requirements of thePatent Code, and that the invention may have other embodiments that willbe obvious to those skilled in the art, and which are intended to becovered by the appended claims.

GENERAL DESCRIPTION Reference numeral 10 of FIGS. 1, 2 and 3 generallyindicates one embodiment of the pressure gauge of this invention, whichcomprises a housing 12, formed from any suitable material, such as diecast aluminum, zinc, plastic, or the like, and defining an open end 15and a closed end 16, and having applied across its open end 15 and edgemounted diaphragm 18, which is enclosed by the back cover member 14.

The housing 12 and diaphragm 18 define a low-pressure chamber 20 whilethe cover member 14 and diaphragm l8 define a high-pressure chamber 22.

The housing 12 mounts a calibratable range spring 24 in the form of leafspring 26 having applied to its free end a mounting plate 28 carrying aplate magnet 30 that cooperates with a helix 32 joumaled in the housingand carrying an indicator arm 34 for cooperation with the indicia 36 ofscale plate 38 that is visible through window 41) in the closed side 16of the housing.

In accordance with this invention, the range spring 24 is calibrated byadjustment device 42 (see FIG. 4) that is operable from the exterior ofhousing 12 to vary the live length of leaf spring 26. The zero positionof the indicator 34 is adjusted by adjustment device 44 (see FIG. 5)that also may be operated from the exterior of the housing 12 to set theindicator arm 34 on the zero datum of scale plate 38.

The lowand high-pressure connections of the gauge 10 are on the sameside of the gauge, they being respectively applied to the threadedlow-pressure connection passageway 50 and the high-pressure threadedpassageway 52 (see FIGS. 1 and 7). The low-pressure passageway 50communicates directly with low-pressure chamber 20 at port 51 (see FIG.2) while the high-pressure passageway 52 communicates with thehighpressure chamber 22 through a bore 54 formed in the housing, anannular chamber or passageway 56 formed about the rim 58 of the housing,spaced openings 60, shown in FIGS. 7 and 8 formed in the rim 62 of thediaphragm, annular chamber or passageway 64 that is defined between thecover member 14 and the diaphragm rim 62, and spaced passageways 65 thatare defined between the cover member 14 and the diaphragm. In the formshown, the gauge 10 is arranged for high-pressure differential serviceand includes annular filler plates 66 and 68, with the filler plate 68being grooved as at 70 to complete communication with the high-pressurechamber 22.

The diaphragm 18 is operably connected to the leaf spring 26 as byconnecting device 72.

During nonnal operation of the gauge, the diaphragm 18 will be deflectedfrom left to right (as viewed in FIG. 3) to deflect leaf spring 26through connection device 72 and through magnet 30 and cause rotation ofhelix 32 to change the position of indicator arm 34.

Pressure gauge 10A Of FIGS. 13-1S is similarly arranged as indicated bycorresponding reference numerals, but includes a modified leaf spring24A, a wishbone-type support structure 71 that mounts the helix 32, anda modified zero adjustment 44A that cooperates with the wishbonestructure 71.

SPECIFIC DESCRIPTION The plate magnet 30 and helix 32 comprises amagnetically coupled mechanism for translating straight line motion torotary motion while avoiding mechanical friction. The deflection of leafspring 26 is about a sufficiently large are so that the magnet 30undergoes essentially straight line movement along the axis of the helix32. One end of the magnet is suitably disposed relative to the helix,which is preferably formed of material having high-magnetic permeabilitycharacteristics, with the result that upon movement of the magnet 30axially of the helix, the helix undergoes rotational follower movementso as to maintain a minimum air gap between the helix and the magnet.

The housing 12 may be formed from die cast zinc, aluminum, moldedplastic or the like, and is suitably shaped to define rim portion 58,upstanding sidewall 00 and front wall 82 that defines window opening 84in which is suitably mounted transparent element 85 that forms theviewing window of the gauge (element 85 being a clear plastic, such asan acrylic, in the illustrated embodiment but clear polycarbonate, glassor other suitable materials may be employed depending on theapplication).

Upstanding from the wall 82 of the housing are a pair of studs (only oneis shown in FIG. 3) that support a scale plate 92 having the indicia 36applied thereto, with the scale plate being received over a projection94 of the respective studs S 0. The scale plate 92 also is secured inplace by being received over similar projections 95 of studs 98, each ofwhich also frictionally receives a tubular diaphragm stop 102 that arethus disposed within the housing 12 on either side of the range springto limit movement to the right of FIG. 3. The housing wall 82 is formedwith suitable mounting screw holes 103 (see FIG. 1). Mounting screwsalso mount a suitable bezel trim piece on front of wall 82.

The diaphragm 18 may be formed from any suitable material, such asneoprene or silicone rubber and the form of the embodiment of FIGS. 7-8is shaped to define the rim 62 together with the rim holes 60, annularflexing indentation that is spaced from the rim portion 62 and defines acentral disclike portion 112 that on one side thereof has a pair ofprojections or studs 116 (see FIGS. 2, 8 and 8A) adapted to frictionallyfit into correspondingly located holes 117 in diaphragm plate 118(projections or studs 1 16 being enlarged as at 119 for this purpose).The diaphragm 18 is also formed with a pair of projections 120 adaptedto be frictionally received in recesses 122 of the low-pressure sidecavity filler 66, the latter engaging the rim 58 of housing 12 about itsopen end 14. The side 121 of the diaphragm rim 62 is of reduced radialdimension as compared to its other side 123 to define with cover 14 thechamber 64.

The diaphragm plate 18 is connected to leaf spring 26 by connectiondevice 72 which comprises a plastic body (see FIG. 3A) having helicalspring 132 (see FIG. 3A) embedded therein, and having extended fromeither end thereof headed stud portions 134 and 136. Stud portion 134 isfrictionally received through opening 138 of diaphragm plate 18 and heldin place by suitable head portion 120, while stud portion 136 isreceived through a suitable opening 139 in leaf spring 26 and held inplace by its head portion 140 (head portions 120 and 140 being clippedto the lengths indicated in FIG. 3 after assembly of connection 72 todiaphragm plate 118 and leaf spring 26). Body 130 is preferably formedfrom a flexible polyurethane to allow connection device 72 toaccommodate movement by bending, and its spring 132 is employed to makeconnection device 72 more rigid in compression for high-pressure ranges(the spring 132 may be omitted when employing the low-pressure diaphragmof FIGS. 9 and 10). The connection of body 130 to the diaphragm plateand leaf spring is sliding friction free (openings 138 and 139 are roundand are filled by the respective stud portions 134 and 136).

Leaf spring 26 is secured cantilevered fashion at one end 142 thereof onwall 144 of housing 12, as by employing suitable screws 146. The otherend 148 thereof has secured thereto by spaced eyelets 150 the mountingplate 28, which in turn has secured thereto by an appropriate rivet 152the plate magnet 30.

The mounting plate 28 in the form shown includes side flanges 154 and156 and end flange 158, for reinforcing purposes, and is formed todefine a relatively rectangular window opening 160 (with which the helix32 is aligned) that includes sides 162 and 164 that extend parallel tothe leaf spring 26, and sides 166 and 168 that extend transverselythereof. Plate 28 also is formed with a smaller rectangular opening 169ad- 35 jacent flange 158.

In the form shown, the magnet 30 is in plate form and is surmounted by arelatively thin plate 171 of high-magnetic permeability defining anoverhanging edge portion 170 that extends parallel to the leaf spring 26and is disposed closely adjacent the helix 32. Plate 171 concentratesthe magnetic lines of force in close adjacency to the helix and improvesthe sensitivity of the gauge.

The adjustment device 42 for calibrating the leaf spring 26 comprisesscrew member having a threaded portion 182 which threadedly receives anelongated slide element 184 defining an edge portion 186 of generallytriangular cross-seetional configuration which forms a fulcrum 188 forleaf spring 26. Screw member 180 is joumaled in housing wall 144 bybeing received through opening 192 formed therein and having itsshoulder 194 and a lock ring 196 that is seated in a groove 198 ofmember 180 being disposed against the housing wall 144. The head 200 ofthe screw member 180 extends into housing outer opening 202.

The head 200 of member 180 remains recessed within the housing opening202, but is positioned for ready access thereto by a screw driver or thelike. The head is formed with a groove 204 in which is received asuitable seal such as O-ring 206 for sealing off the housing at thispoint.

As indicated in FIG. 2, the slide element 184 extends transversely ofthe leaf spring 26 and exceeds its width somewhat. As the screw member180 is joumaled in the housing, on rotation of same, slide element 184,being held against rotation by its application against the leaf spring26, will move lengthwise of the leaf spring to provide the fulcrumsetting desired.

The helix 32 is joumaled (see FIG. 6) by being applied to a saddleelement 210 that is secured between spaced studs 212 and 214 by therespective screws 216 and 218. The helix is mounted between jeweledpivot bearings 220 and 222 mounted in the respective arms 223 and 225 ofthe saddle 210, with the bearing 222 being adjustably mounted.

As indicated in FIGS. 2 and 6, the helix 32 is mounted in alignment withthe window 160 of the leaf spring mounting plate 28, and extendsgenerally perpendicular to the leaf spring. The helix 32, being formedof a high-magnetic permeability material, aligns itself in the field ofmagnet 30 to maintain the minimum air gap between the magnet and theedges of the helix closest to same and to its plate 171. As the magnetmoves parallel to the axis of the helix, the helix rotates to maintainthis minimum air gap.

The adjustment device 44 (see FIG. 5) generally comprises a screw member230 having a head I portion 232 which is grooved as at 234 to receive alock ring 235 and extends through opening 236 of the housing 12. Screwmember 230 is grooved as at 238 to receive suitable O-ring 240 forsealing off the housing at the opening 236.

Screw member 230 includes a threaded portion 242 on which is received aslide element 244 that includes a flange portion 246 of squareconfiguration and a cylindrical sleeve portion 248 over which isfrictionally seated a coil-type tension spring 250 having a hooked endportion 252 that is received through opening 254 formed in he flange 158of the leaf spring mounting plate 28.

The rectilinear edge 256 of slide 244 cooperates with wall surface 258of housing 12, and edges 255 and 257 cooperate with housing walls 259and 261, to maintain the slide member 244 against turning on rotation ofscrew member 230 by the application thereof of a suitable tool to itshead 232. Thus, the slide member 244 will move axially of the screwmember 230 on rotation of the latter to provide the zero adjustment forthe gauge 10, thereby permitting the indicator arm 34 that is carried bythe helix 32 to be set on the zero reading of the scale indicia 36.

The cover 14 defines an upstanding sidewall or rim 262, an annularrecess 264 at the base of the rim 262, and a ridge 266 (see FIG. 11)defined by upstanding walls 268 and 270 on which the diaphragm seatsinwardly of the diaphragm openings 60 (with the side 121 of thediaphragm rim being spaced therefrom to define annular chamber 64). Thecover member is indented as at 272 to define spaced radial grooves 274that form passageways 65 that connect chamber 64 with chamber 22. Thehousing rim 58 is grooved as at 276 to define the annular distributingchamber 56 that is communicated with by the housing laterally extendingpassage 54.

The relationship between the diaphragm openings 60 and chambers 56 and64 avoids having to line up diaphragm openings 60 in any special mannerrelative to either housing 12 or cover 14 in assembling the gauge 10, asopenings 60 provide the necessary communication through the diaphragmregardless of how openings 60 are disposed relative to housing bore 54about central axis of the gauge.

The cover 14 is formed with four spaced semispherical protuberances 280to prevent the diaphragm from snugly contacting the inside surface ofcover member 14. In application to the housing 12, the edge 282 of itswall 262 is turned over against annular shoulder 284 of housing wall rim58 to compress the rim 62 of the diaphragm therebetween for sealingpurposes.

In the showing of FIGS. 9 and 10, a diaphragm 18A is illustrated that issuitable for low-pressure differential purposes and comprises rimportion 62A, flexible indentation 110A, and central portion 112A ofincreased diameter, to which is attached modified diaphragm plate 118A,the diaphragm being formed on one side thereof with suitable reinforcingribs 288 and on the other side thereof with suitable headed studs 200that are adapted to be frictionally received through suitable openings292 in the diaphragm plate 118A. The diaphragm plate 118A is secured bycoupling device 72 to the leaf spring 26 in the position illustrated inFIG. 3 for the diaphragm 18 and its plate 118, with the filler plates 66and 68 being eliminated, for low-pressure differential applications.Diaphragm 18A at its rim 62A is formed with spaced passages 60A thatserve the same purpose as passages 60 of diaphragm In the embodiment Aof P168. 13-15, the gauge spring 244. comprises leaf spring 26A fixed tothe housing 12A, by having one of its ends 142A secured thereto bysuitable screws 146A under spring retainer plate 300, The other end 148Aof the leaf spring includes an extension 302 that has secured theretothe plate magnet 30 and its plate 171, as by employing appropriate rivet152A.

The wishbone structure 71 generally comprises a wishboneshaped member304 formed from a suitable light weight material, such as aluminum of asuitable gauge, and defining spaced arms 306 and 308 that are mounted onthe respective housing studs A (FIG. 14), as by employing suitablescrews 310. Intermediate its arms 306 and 308 the wishbone member 304includes projecting portion 312 provided with a pair of projections 314over which scale plate 92A is force fitted.

Wishbone member 304 includes projecting end portion 316 that is formedto define spaced mounting arms 318 and 320 (see FIG. 15) between whichthe helix 32 is journaled, with the helix 32 of the embodiment of FIGS.13-15 being disposed adjacent magnet 30 and its plate 171 in the mannerindicated in FIGS. 13 and 15 to provide the relationship alreadydescribed with reference to gauge 10.

Wishbone projecting end portion 316 is formed with an opening 322through which the screw member 230A of the modified zero adjustmentdevice 44A projects for cooperation with a suitable nut structurecarried by the wishbone member 304 in alignment with opening 322, whichmay be in the form of the U-type clip nut structure 324 (of the typemanufactured by Tinnerman Products, Inc.) that is applied over thewishbone projecting end portion 316.

The screw member 230A has its threaded portion 242A threadedly engagewith the nut structure 324 and is journaled in opening 236 of thehousing by being held between lock ring 235 and washer 330.

The leaf spring 148A is secured to the diaphragm by connecting device72.

By the application of a suitable tool to the head 232A of the screwmember 230A, screw member 230A may be rotated to move nut structure 324,and thus the end portion 316 of wishbone member 304, axially of thescrew member 230A to provide the zero adjustment for the gauge 10A.

The gauge 10A is otherwise substantially identical to gauge 10, asindicated by corresponding reference numerals.

The foregoing description and the drawings are given merely to explainand illustrate the invention and the invention is not to be limitedthereto, except insofar as the appended claims are so limited, sincethose skilled in the art who have the disclosure before them will beable to make modifications and variations therein without departing fromthe scope of the invention.

We claim:

1. In a gauge that comprises a differential pressure capsule having aflexible diaphragm separating highand low-pressure chambers, saidcapsule including a housing in which a helix is journaled for rotationabout its axis, with the helix having an indicator connected thereto anda magnet for producing rotational movement of said helix in response tolinear movement of said magnet alongside the axis of the helix, and azero datum adjacent to which the indicator is disposed, the improvementwherein:

said magnet is mounted on a leaf spring member,

said leaf spring member being anchored to said housing cantileverfashion at one end thereof and including a window adjacent the other endthereof,

said leaf spring member being disposed to extend generally transverselyof the axis of said helix with said helix aligned with said window,

said magnet being mounted on said leaf spring member adjacent saidwindow in magnetic attraction relation to said helix,

said diaphragm being connected to said spring member to shift saidmagnet substantially parallel to the axis of said helix on changes ofpressure in one or more of said chambeta,

an adjustment device for adjusting the spring rate of said spring memberand comprising:

a threaded member journaled in said housing in substantially parallelclosely spaced relation to said spring member adjacent said one end ofsaid spring member and having a threaded portion of same disposedbetween said one end thereof and said window,

and a slide element threadedly received on said threaded portion of saidthreaded member and extending transversely of said spring member,

said slide element having a length that is at least substantially equalto the width of said spring member, and being formed to define a V-shaperidge engaging said spring member,

means for setting the indicator on the zero datum,

said setting means comprising:

a second threaded member journaled in said housing adjacent the helixand including a threaded portion extending parallel to the helix,

a second slide element threadedly received on said second threadedmember threaded portion,

means for maintaining said second slide element against rotation of saidsecond threaded member,

said second threaded member being disposed in substantial alignment withthe other end of said spring member,

and a tension spring connected between said second slide element andsaid other end of said spring member,

and means for selectively rotating said threaded member.

2. The improvement set forth in claim 7 wherein:

the interior of said housing serves as the low-pressure chamber on oneside of the diaphragm,

and wherein the high-pressure chamber is defined on the other side ofthe diaphragm by a dished cover member overlying said diaphragm andsecured to said housing.

3. The improvement set forth in claim 9 wherein:

said housing is provided with lowand'high-pressure connections on thesame side of said diaphragm,

said diaphragm having at least one passageway through the rim thereof,

one of said connections communicating with the passageway through thediaphragm rim;

said diaphragm rim being in fluidtight relationship between said housingand said cover member,

and means for communicating said high-pressure chamber with saidpassageway in said rim including an annular groove in the respectiveportions of said housing and cover member between which the rim of thediaphragm is clamped,

said passageway communicating between said grooves.

4. The improvement set forth in claim lit) wherein:

the annular groove of said cover member is connected by at least oneradially directed passageway to said high-pressure chamber.

5. The improvement set forth in claim 9 wherein:

said threaded members are in said low-pressure chamber,

and including O-ring seal means about the respective threaded membersand in sealing engagement with said housing to seal off saidlow-pressure chamber at said threaded members.

6. The improvement set forth in claim 12 wherein:

said second threaded member includes a flange thereabout in engagementwith an outwardly facing wall of said hous- 8,

said flange of said second threaded member and said tension springserving as the means for journaling said second threaded member in saidhousing.

7. In a gauge that includes linear to rotary motion transforming meansincluding a helix journaled for rotation about its axis, with the helixhaving an indicator connected thereto, a magnet for producing rotationalmovement of said helix in response to linear movement of the magnetalongside the axis of the helix, and a housing for the helix and magnet,the improvement wherein:

said magnet is mounted on a leaf spring member,

said leaf spring member being anchored to said housing cantileverfashion at one end thereof,

said leaf spring member being disposed to extend generally transverselyof the axis of said helix with said helix aligned with said springmember,

said magnet being mounted on said leaf spring member adjacent to and inmagnetic attraction relation to said helix,

sensing means connected to said spring member to shift said magnetsubstantially parallel to the axis of said helix and comprising aflexible diaphragm separating highand lowpressure chambers in the gauge,

and an adjustment device for adjusting the spring rate of said springmember and comprising:

a threaded member journaled in said housing in substantially parallelclosely spaced relation to said spring member adjacent said one end ofsaid spring member and having a threaded portion of same disposedbetween said one end thereof and said magnet,

and a slide element threadedly received on said threaded portion of saidthreaded member and extending transversely of said spring member,

said slide element having a length that is at least substantially equalto the width of said spring member, nd being formed to define a fulcrumengaging said spring member and extending transversely thereof,

means for setting the indicator on a zero datum,

said setting means comprising:

a second threaded member journaled in said housing adjacent the helixand including a threaded portion extending parallel to the helix,

means for transforming rotary motion of said second threaded member intomovement of said magnet parallel to the axis of said helix to set theindicator on the datum,

a wishbone structure having its arms secured to said housing to mountsaid wishbone structure cantilever fashion to define a projecting endportion,

said helix being carried by said wishbone structure adjacent saidprojecting end portion thereof,

said wishbone structure including nut means threadedly engaged with saidsecond threaded member to provide said transforming means,

said leaf spring member including an off center extension at the otherend thereof,

said magnet being mounted on said leaf spring member extension.

8. The improvement set forth in claim 7 wherein:

the interior of said housing serves as the low-pressure chamber on oneside of the diaphragm,

and wherein the high-pressure chamber is defined on the other side ofthe diaphragm by a dished cover member overlying said diaphragm andsecured to said housing.

9. The improvement set forth in claim 8 wherein:

said housing is provided with lowand high-pressure connections on thesame side of said diaphragm,

said diaphragm having a peripheral rim and at least one passagewaythrough the rim thereof,

one of said connections communicating with passageway through thediaphragm rim,

said diaphragm rim being in fluidtight relationship between said housingand said cover member,

and means for communicating said high-pressure chamber with said onepassageway in said rim including annular grooves in the respectiveportions of said housing and cover member between which the rim of thediaphragm is clamped,

said one passageway communicating with said high pressure chamberbetween said grooves.

1 1. The improvement set forth in claim 9 wherein:

the annular groove of said cover member is connected by at least oneradially directed passageway to said high-pressure chamber.

H0. The improvement set forth in claim 8 wherein:

said threaded members are in said low-pressure chamber,

and including O-ring seal means about the respective threaded membersand in sealing engagement with said housing to seal off saidlow-pressure chamber at said threaded members.

the

IUlllZfl (H37 12. In a differential pressu re sfiisitive device whereina flexible diaphragm is mounted in a housing with means to apply lowpressure on one side of the diaphragm and high pressure on the otherside, with the housing including top and bottom members, and thediaphragm including a rim in circumambient relation thereabout, theimprovement comprising:

high-pressure and low-pressure connections to one of said housingmembers on the same side of the diaphragm,

said diaphragm having at least one passageway through said rim thereof,

means for clamping said diaphragm rim between said top and bottomhousing members in fluid tight relationship therebetween,

means for communicating the space on the side of the diaphragm oppositethe side on which said connections are located, with said one passagewayin said diaphragm rim,

said communicating means including annular grooves defined by said rimand the respective surfaces of the top and bottom housing membersbetween which said rim of the diaphragm is clamped, with said groovesbeing disposed on either side of said diaphragm,

a passageway from one of said connections communicating with the grooveof said grooves that is on said same side of said diaphragm,

said diaphragm passageway communicating between said grooves,

means connecting the other of said connections to said same side of saiddiaphragm,

and means for connecting the other groove of said grooves to the otherside of said diaphragm,

13. A differential pressure sensitive device in accordance with claim 12in which the other annular groove of said grooves is connected by atleast one passageway to the space between the diaphragm and said otherhousing member to form the second mentioned connecting means.

14. A differential pressure sensitive device in accordance with claim 13in which:

the rim of the diaphragm is clamped in fluidtight relationship betweenthe top and bottom housing members inwardly of the location of saidpassageway in the diaphragm rim.

B5. In a gauge that includes linear to rotary motion transforming meansincluding a helix joumaled for rotation about its axis, with the helixhaving an indicator connected thereto, a magnet for producing rotationalmovement of said helix in 7 response to linear movement of the magnetalongside the axis All! of the helix, and a housing for the helix andmagnet, the improvement wherein:

said magnet is mounted on a leaf spring member,

said leaf spring member being anchored to said housing cantileverfashion at one end thereof and a mounting plate on the other endincluding a window therein,

said leaf spring member being disposed to extend generally transverselyof the axis of said helix with said helix aligned with said window,

said magnet being mounted on said leaf spring member adjacent to and inmagnetic attraction relation to said helix,

sensing means connected to said spring member to shift said magnetsubstantially parallel to the axis of said helix,

and an adjustment device for adjusting the spring rate of said springmember and comprising:

a threaded member joumaled in said housing in substantially parallelclosely spaced relation to said spring member adjacent said one end ofsaid spring member and having a threaded portion of same disposedbetween sad one end thereof and said window,

and a slide element threadedly received on said threaded portion of saidthreaded member and extending transversely of said spring member,

said slide element having a length that is at least substantially equalto the width of said spring member, and being formed to define aV-shaped ridge engaging said pring member,

means for setting the indicator on a zero datum,

said setting means comprising:

a screw member joumaled in said housing adjacent the helix and includinga threaded portion extending parallel to the helix,

and means for transforming rotary motion of said screw memberintomovement of said magnet parallel to the axis of said helix to setthe indicator on the datum,

a wishbone structure having its arms secured to said housing to mountsaid wishbone structure cantilever fashion to define a projecting endportion,

- said helix being carried by said wishbone structure adjacent said endportion thereof,

said wishbone structure including net means threadedly en gaged withsaid screw member to provide said transforming means. 16. Theimprovement set forth in claim 15 wherein: said leaf spring memberincludes an off center extension at the other end thereof, said magnetbeing mounted on said leaf spring extension.

i? q 1 mm A? n I: r rr vw 1" cwimiuruuxmim U KAQEQAJMiULUN Patent 3,6A5, 1A0 Dated Februar 29, 1972 z vmorw JAMES w. PHILLlPS gnd RICHARD s.ZOLUDOW I: is certified that error appears in the abovc-identifid patentand that said Latmzs Patent are hereby corrected aa shown below:

E Column 7, line 27, for "7" read 1 7 m Column 7, line 3.4, for "9 read.2

ColumnY'Y, line 40, semicolon should be a comma Column 7', line 49, for"10" read 3 C o1umn 7, line '53, for 9" read -'f- 2 Column 7, line 59,for, "12 read e .5 Column 8, line 21, for "nd". read E a'nd Column8,'.-- 1ine 66, for "11" re'ad 1O -cqlumn 8, line 70, for "10" read 11.

Column '10, between lines 35 and 36 insert said setting means furthercomprising: Column 10, line 41, fbr'lY'rdeiz raql nut :EDWARDMQFLLETCIER,-IJIRQ GR'GBERTGQTTSCHALK'; u i A t lg? fficrj q H 1 ICommissioner- ;E 1 -,e nt v

1. In a gauge that comprises a differential pressure capsule having aflexible diaphragm separating high- and low-pressure chambers, saidcapsule including a housing in which a helix is journaled for rotationabout its axis, with the helix having an indicator connected thereto anda magnet for producing rotational movement of said helix in response tolinear movement of said magnet alongside the axis of the helix, and azero datum adjacent to which the indicator is disposed, the improvementwherein: said magnet is mounted on a leaf spring member, said leafspring member being anchored to said housing cantilever fashion at oneend thereof and including a window adjacent the other end thereof, saidleaf spring member being disposed to extend generally transversely ofthe axis of said helix with said helix aligned with said window, saidmagnet being mounted on said leaf spring member adjacent said window inmagnetic attraction relation to said helix, said diaphragm beingconnected to said spring member to shift said magnet substantiallyparallel to the axis of said helix on changes of pressure in one or moreof said chambers, an adjustment device for adjusting the spring rate ofsaid spring member and comprising: a threaded member journaled in saidhousing in substantially parallel closely spaced relation to said springmember adjacent said one end of said spring member and having a threadedportion of same disposed between said one end thereof and said window,and a slide element threadedly received on said threaded portion of saidthreaded member and extending transversely of said spring member, saidslide element having a length that is at least substantially equal tothe width of said spring member, and being formed to define a V-shaperidge engaging said spring member, means for setting the indicator onthe zero datum, said setting means comprising: a second threaded memberjournaled in said housing adjacent the helix and including a threadedportion extending parallel to the helix, a second slide elementthreadedly received on said second threaded member threaded portion,means for maintaining said second slide element against rotation of saidsecond threaded member, said second threaded member being disposed insubstantial alignment with the other end of said spring member, and atension spring connected between said second slide element and saidother end of said spring member, and means for selectively rotating saidthreaded member.
 2. The improvement set forth in claim 7 wherein: theinterior of said housing serves as the low-pressure chamber on one sideof the diaphragm, and wherein the high-pressure chamber is defined onthe other side of the diaphragm by a dished cover member overlying saiddiaphragm and secured to said housing.
 3. The improvement set forth inclaim 9 wherein: said housing is provided with low- and high-pressureconnections on the same side of said diaphragm, said diaphragm having atleast one passageway through the rim thereof, one of said connectionscommunicating with the passageway through the diaphragm rim; saiddiaphragm rim being in fluidtight relationship between said housing andsaid cover member, and means for communicating said high-pressurechamber with said passageway in said rim including an annular groove inthe respective portions of said housing and cover member between whichthe rim of the diaphragm is clamped, said passageway communicatingbetween said grooves.
 4. The improvement set forth in claim 10 wherein:the annular groove of said cover member is connected by at least oneradially directed passageway to said high-pressure chamber.
 5. Theimprovement set forth in claim 9 wherein: said threaded members are insaid low-pressure chamber, and including O-ring seal means about therespective threaded members and in sealing engagement with said housingto seal off said low-pressure chamber at said threaded members.
 6. Theimprovement set forth in claim 12 wherein: said second threaded memberincludes a flange thereabout in engagement with an outwardly facing wallof said housing, said flange of said second threaded member and saidtension spring serving as the means for journaling said second threadedmember in said housing.
 7. In a gauge that includes linear to rotarymotion transforming means including a helix journaled for rotation aboutits axis, with the helix having an indicator connected thereto, a magnetfor producing rotational movement of said helix in response to linearmovement of the magnet alongside the axis of the helix, and a housingfor the helix and magnet, the improvement wherein: said magnet ismounted on a leaf spring member, said leaf spring member being anchoredto said housing cantilever fashion at one end thereof, said leaf springmember being disposed to extend generally transversely of the axis ofsaid helix with said helix aligned with said spring member, said magnetbeing mounted on said leaf spring member adjacent to and in magneticattraction relation to said helix, sensing means connected to saidspring member to shift said magnet substantially parallel to the axis ofsaid helix and comprising a flexible diaphragm separating high- andlow-pressure chambers in the gauge, and an adjustment device foradjusting the spring rate of said spring member and comprising: athreaded member journaled in said housing in substantially parallelclosely spaced relation to said spring member adjacent said one end ofsaid spring member and having a threaded portion of same disposedbetween said one end thereof and said magnet, and a slide elementthreadedly received on said threaded portion of said threaded member andextending transversely of said spring member, said slide element havinga length that is at least substantially equal to the width of saidspring member, nd being formed to define a fulcrum engaging said springmember and extending transversely thereof, means for setting theindicator on a zero datum, said setting means comprising: a secondthreaded member journaled in said housing adjacent the helix andincluding a threaded portion extending parallel to the helix, means fortransforming rotary motion of said second threaded member into movementof said magnet parallel to the axis of said helix to set the indicatoron the datum, a wishbone structure having its arms secured to saidhousing to mount said wishbone structure cantilever fashion to define aprojecting end portion, said helix being carried by said wishbonestructure adjacent said projecting end portion thereof, said wishbonestructure including nut means threadedly engaged with said secondthreaded member to provide said transforming means, said leaf springmember including an off center extension at the other end thereof, saidmagnet being mounted on said leaf spring member extension.
 8. Theimprovement set forth in claim 7 wherein: the interior of said housingserves as the low-pressure chamber on one side of the diaphragm, andwherein the high-pressure chamber is defined on the other side of thediaphragm by a dished cover member overlying said diaphragm and securedto said housing.
 9. The improvement set forth in claim 8 wherein: saidhousing is provided with low- and high-pressure connections on the sameside of said diaphragm, said diaphragm having a peripheral rim and atleast one paSsageway through the rim thereof, one of said connectionscommunicating with the passageway through the diaphragm rim, saiddiaphragm rim being in fluidtight relationship between said housing andsaid cover member, and means for communicating said high-pressurechamber with said one passageway in said rim including annular groovesin the respective portions of said housing and cover member betweenwhich the rim of the diaphragm is clamped, said one passagewaycommunicating with said high pressure chamber between said grooves. 10.The improvement set forth in claim 8 wherein: said threaded members arein said low-pressure chamber, and including O-ring seal means about therespective threaded members and in sealing engagement with said housingto seal off said low-pressure chamber at said threaded members.
 11. Theimprovement set forth in claim 9 wherein: the annular groove of saidcover member is connected by at least one radially directed passagewayto said high-pressure chamber.
 12. In a differential pressure sensitivedevice wherein a flexible diaphragm is mounted in a housing with meansto apply low pressure on one side of the diaphragm and high pressure onthe other side, with the housing including top and bottom members, andthe diaphragm including a rim in circumambient relation thereabout, theimprovement comprising: high-pressure and low-pressure connections toone of said housing members on the same side of the diaphragm, saiddiaphragm having at least one passageway through said rim thereof, meansfor clamping said diaphragm rim between said top and bottom housingmembers in fluid tight relationship therebetween, means forcommunicating the space on the side of the diaphragm opposite the sideon which said connections are located, with said one passageway in saiddiaphragm rim, said communicating means including annular groovesdefined by said rim and the respective surfaces of the top and bottomhousing members between which said rim of the diaphragm is clamped, withsaid grooves being disposed on either side of said diaphragm, apassageway from one of said connections communicating with the groove ofsaid grooves that is on said same side of said diaphragm, said diaphragmpassageway communicating between said grooves, means connecting theother of said connections to said same side of said diaphragm, and meansfor connecting the other groove of said grooves to the other side ofsaid diaphragm,
 13. A differential pressure sensitive device inaccordance with claim 12 in which the other annular groove of saidgrooves is connected by at least one passageway to the space between thediaphragm and said other housing member to form the second mentionedconnecting means.
 14. A differential pressure sensitive device inaccordance with claim 13 in which: the rim of the diaphragm is clampedin fluidtight relationship between the top and bottom housing membersinwardly of the location of said passageway in the diaphragm rim.
 15. Ina gauge that includes linear to rotary motion transforming meansincluding a helix journaled for rotation about its axis, with the helixhaving an indicator connected thereto, a magnet for producing rotationalmovement of said helix in response to linear movement of the magnetalongside the axis of the helix, and a housing for the helix and magnet,the improvement wherein: said magnet is mounted on a leaf spring member,said leaf spring member being anchored to said housing cantileverfashion at one end thereof and a mounting plate on the other endincluding a window therein, said leaf spring member being disposed toextend generally transversely of the axis of said helix with said helixaligned with said window, said magnet being mounted on said leaf springmember adjacent to and in magnetic attraction relation to said helix,sensing means connected to said spring member to shift said magnetsubstantially parallel to the axis of said helix, and an adjustmentdevice for adjusting the spring rate of said spring member andcomprising: a threaded member journaled in said housing in substantiallyparallel closely spaced relation to said spring member adjacent said oneend of said spring member and having a threaded portion of same disposedbetween sad one end thereof and said window, and a slide elementthreadedly received on said threaded portion of said threaded member andextending transversely of said spring member, said slide element havinga length that is at least substantially equal to the width of saidspring member, and being formed to define a V-shaped ridge engaging saidpring member, means for setting the indicator on a zero datum, saidsetting means comprising: a screw member journaled in said housingadjacent the helix and including a threaded portion extending parallelto the helix, and means for transforming rotary motion of said screwmember into movement of said magnet parallel to the axis of said helixto set the indicator on the datum, a wishbone structure having its armssecured to said housing to mount said wishbone structure cantileverfashion to define a projecting end portion, said helix being carried bysaid wishbone structure adjacent said end portion thereof, said wishbonestructure including net means threadedly engaged with said screw memberto provide said transforming means.
 16. The improvement set forth inclaim 15 wherein: said leaf spring member includes an off centerextension at the other end thereof, said magnet being mounted on saidleaf spring extension.